Climate scientists take a lot of abuse. The political opposition to climate science in some countries breeds nasty attacks on the scientists themselves. Penn State’s Michael E. Mann, for example, became a favorite target after his work on tree-ring records of past climate produced a “hockey stick” graph showing that a gradual cooling trend flipped into sharp, human-caused warming.

In 2012, Mann decided he’d had enough and did something few other scientists have—he filed a defamation lawsuit. After years bouncing around in court, with the defendants appealing decisions that would let the case proceed, the suit’s last obstacle was cleared Monday as the Supreme Court declined to hear an appeal. A 2016 decision by a District of Columbia court will stand, and the case will now have to be heard.

The original suit was prompted by articles written by Conservative columnist and radio show host Mark Steyn and Rand Simberg of the Conservative Enterprise Institute. The articles claimed that Mann’s research was fraudulent—that he had intentionally manipulated data. And Simberg added a regrettable analogy that Steyn quoted in his piece: “Mann could be said to be the Jerry Sandusky of climate science, except for instead of molesting children, he has molested and tortured data.”